1. Field of the Invention
The present invention relates to geothermal vertical heat exchanger systems and more particularly pertains to a new U-bend pipe spacer for separating vertical portions of a U-bend pipe in a bore in the ground during installation of the U-bend pipe in a geothermal vertical heat exchanger system.
2. Description of the Prior Art
The purpose of a geothermal heat exchanger is to exchange energy with the Earth by circular a water/antifreeze solution through plastic pipe that is buried below the Earth's surface. In one type of geothermal heat exchanger, the installation procedure first requires the drilling of a vertical bore into the ground. Next, a U-bend fitting is fused onto the lower ends of two polyethylene plastic pipes to form a U-bend pipe which is then inserted into the bore. A grout such as a 20% bentonite grout is pumped into the bore via a pipe (called a tremie) inserted into the bore.
The bentonite grout that is used to fill the bore acts as an insulator by impairing heat transfer between the elongate portions of the U-bend pipe and the surrounding soil. The insulating effect of the ground thereby requires longer bore lengths. Using a higher thermal conductivity grout material helps to eliminate this insulating effect. However, most States mandate grouting with bentonite to ensure that the bore is sealed tight to prevent contaminated from entering aquifers below the ground surface. Thermally enhanced bentonite grouts are becoming available but are costly and labor intensive to use.
Known prior art includes U.S. Pat. No. 4,715,429; U.S. Pat. No. 4,867,229; U.S. Pat. No. 4,867,229; U.S. Pat. No. 5,590,715; U.S. Pat. No. 4,595,059;U.S. Pat. No. 2,554,661; U.S. Pat. No. 5,372,016; U.S. Pat. No. 5,004,374; U.S. Pat. No. 388,439; U.S. Pat. No. 447,297; U.S. Pat. No. 4,160,477; and U.S. Pat. No. 5,072,786.
While these devices fulfill their respective, particular objectives and requirements, the aforementioned patents do not disclose a new U-bend pipe spacer. The inventive device includes a biasing member with a pair of elongate portions having free ends biased apart from one another. The elongate portions of the biasing member is resiliently deflectable from a relaxed position to a deflected portion such that the free ends of the elongate portions of the biasing member are positioned closer to each other when the elongate portions are in the deflected position. The spacer also includes a pair of clip members each comprising a body having a concave arcuate side face defining a channel and a tremie hook is coupled to the body. The tremie hook has a concave side. The body of a first of the clip members is coupled to the free end of a first of the elongate portions of the biasing member and the body of a second of the clip members is coupled to the free end of a second of the elongate portions of the biasing member with the channels of the clip members facing outwardly away from each other. The channel of the body of the first clip member is designed for receiving a first elongate portion of a U-bend pipe therein and the channel of the body of the second clip member is designed for receiving a second elongate portion of the U-bend pipe therein. The bodies of the clip members are positioned adjacent each other when the elongate portions of the biasing member are positioned in the deflected position. In this deflected position, the tremie hooks of the clip members overlap each other so that the concave sides of the tremie hooks face one another and define a tremie space therebetween for extending a tremie pipe therethrough which holds the elongate portions of the biasing member in the deflected position as long as the tremie pipe is in the tremie space.
In these respects, the U-bend pipe spacer according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in so doing provides an apparatus primarily developed for the purpose of separating vertical portions of a U-bend pipe in a bore in the ground during installation of the U-bend pipe in a geothermal vertical heat exchanger system.